Sounds like it'll work just fine. If it's an argentine it has a high probability of going into hibernation regardless of the temperatures you maintain. If, or even when, this happens be sure to turn the heat off so your GU doesn't burn through all it's reserves too quickly. These are very adaptable critters that handle cooler temperatures just fine. I've left mine outside when temperatures dropped below freezing and everything was fine. Their retreat just needs to be below the frost line.